Over on Reddit, users are diving into some fun physics questions. One interesting query comes from gothreepwood101. They ask, “If I had a metal pole long enough to reach from England to France and someone pulls on one end, would the other end move instantly?”
At first glance, it seems straightforward. Pull one end of a metal pole, and the other should move right away, right? But it’s not that simple. If you think the answer is “yes,” you’ve just broken a fundamental rule of physics: nothing can travel faster than the speed of light, which is about 299,792 kilometers per second.
One might wonder if the other end of the pole would move at the speed of light. This idea isn’t accurate either. The real answer lies in understanding how materials behave.
When you pull on a metal pole, the initial motion travels through a series of atoms. Think of these atoms as a tightly knit community that relies on their bonds to communicate. When you tug on one end, it creates a wave that moves through the pole. This wave travels at the speed of sound in the material, not light.
To illustrate this, material scientist Brian Haidet demonstrated the concept. He conducted a straightforward experiment where he struck one end of a pole and measured the time it took for the signal to travel to the other end. The results showed that this signal moved at the speed of sound in steel, around 5,130 meters per second.
Now, let’s break down how fast that really is over a distance. The closest distance between England and France is about 33 kilometers (20 miles). If we use the speed of sound in steel, it would take roughly 6.43 seconds for a pull at one end to be felt at the other. Meanwhile, light would cover that same distance in a mere 0.00011 seconds. The difference is astounding!
User reactions on social media often highlight how counterintuitive this concept is. Many people feel that solids should transmit forces instantly, yet the reality shows us the fascinating limitations imposed by physics.
In conclusion, while you might be eager for a quick tug on that hypothetical pole, remember that even solid objects have their limits! For more on the mechanics of sound and waves, you can check out the in-depth resources from The Physics Van.
